A strike to the brachial plexus cause fainting - technically, not a knockout. Although the recipient will not walk for 20 minutes.
In this case, he got sand in his vagina too.
For my non-fighting FRiends, here is a great technique that any dingdong can learn to quickly knock out an aggressive thug.
Notice how Jay Lee winds up his right hand as if he's looking to hit the thug with that hand while blocking with his left.
Then he delivers the "Brachial Stun" to the brachioplexus, thereby knocking out and removing the legs of his opponent for 15-20 minutes.
The thug still does not know what happened.
A closer look
Now you know how.
It's enough to see my video to learn this simple technique, a drunk or untrained, angry fool will drop like you saw in both videos.
:)